Diaphbagm-fob electrolytic cells



(No Model.)

B. A. LE SU EUR. DIAPHRAGM FOR ELEGTROLYTIU CELLS.

N0.518,786. U 4 PatentedApr.24,1894.

UNITED STATES PATENT OFFICE.

ERNEST ARTHUR LE SUEUR, OF OTTAWA, CANADA.

DIAPHRAGM FOR ELECTROLYTIC' CELLS.

SPECIFICATION forming part of Letters Patent No. 518,786, dated April24, 1894.

' Application filed August 29,1892. Serial No. 444,488. (No model.)

T on whom it may concern:

Be it known that I, ERNEST ARTHUR Ln SUEUR, a subject of the Queen ofGreat Britain,residing at Ottawa, in the Province of Ontario, Dominionof Canada, have invented certain new and useful Improvements inDiaphragms for Electrolytic Cells, of which the following is aspecification, reference being had therein to the accompanying drawings.

In an electrical apparatus designed for the decomposition of common saltand similar chemical substances it is necessary to interpose a diaphragmbetween the positive and negative electrodes. The office of thediaphragm is to keep the products of decom'po-j sition in theirrespective portions of the cell. If some such device were not employedthe two would mix and besides depreciating the purity of the products ofdecomposition, the working of the apparatus would be seriously affected,from the fact that the current would expend itself in decomposing thesecondary products formed by the combination of soda and chlorineinstead of expending its energy in decomposing the brine proper. Greatdifficulty has been experienced in obtaining suitable material andarrangements of the same for the diaphragms insuch cells. The difficultyis due to the fact that a diaphragm which is impervious to the passageof the liquids and will therefore keep them wholly separate is apt tointerpose a high resistance to the passage of the current. The thing tobe desired is a durable diaphragm which will perfectly separate thecontents of the cell and will at the same time be of very lowresistance. Vegetable parchment has been employed and aifords anexcellent diaphragm both as to non-porosity and low resistance but itlacks durability in a cell in which a corrosive substance like chlorineis evolved and will go to pieces in a short time. Asbestus on the otherhand will resist the action of the chlorine, but if used in a sheet thinenough to be of low resistancgthe liquid will pass through it toofreely, whileiif it is made thick enough to prevent the passing of theproduce a diaphragm which shall obviate these objections and by the useof which the A diffusion of the liquid contents of the cell may beprevented while the resistance is maintained at a minimum, and itconsists in a diaphragm composed of two layers or sheets of materialseparated by a mass of liquid, the

of the level of the liquid in the cell, all as more particularlyhereinafter set forth and as is pointed out in the claims which areappended hereto and made a part hereof.

In the drawings I have shown my invention in the best form now known tome, and in the following description of my improvement I willspecifically refer thereto.

In said drawings, Figure l is a vertical section of a cell or containingvessel showing my improved diaphragm. Fig. 2 shows the upper portion ofthe central frame hereinafter referred to. Fig. 3 is a perspective of aportion of the side frame in which the carbon electrode is supported.Fig. 4 is a similar view of the other side frame in which the negativeelectrode is supported. Fig. 5 is a detail on a smaller scale, which ishereinafter referred to.

My invention is simple-and will be readily understood from the followingdescription in which the construction is set forth. The outer containingvessel or cell is shown at A, and may be of any well-known shape orconstruction. The brine or solution which is to be decomposed iscontained within this cell, the level of the liquid therein beingindicated at a. An overflow isshown at b which serves to. prevent theliquid in the positive electrode compartment of the cell from risingabove the level indicated. If required a similar overflow may beprovided in the negative electrode compartment, as indicated by dottedlines in Fig. 1. A frame, which I have termed the central frame is shownat c and is constructed of suitable material as lead, for example, andmade to fit the interior of the cell A closely. The cross piece d at thetop of the frame 0 is joined to the upright portions level of which issomewhat higher than that of the frame somewhatbelow the top thereof asshownFig. 2 so as to leavethe uprights projecting above the cross piece.A series of holes 6 which pass vertically through the cross piece at aremade therein. frainecare made true so that a diaphragm or layer ofmaterial may be securely clamped thereon said layer or diaphragm beingsecured IOO The sides of the the passage of the current. The layer f issecured in place by clamping it betweenthe frame a and a side frame gwhich supports the positive or carbon electrode 71.. A series of rodsare placed in the frame g crosswise thereof and adjacent the layer orsheet f. The rods 7c are preferably secured in place by being laid inaslot or recess provided ateach end of each rod in the uprightportion ofthe side frame g as shown Fig. 3. The rods it serve to prevent theasbestus layer f from bulging toward the carbon electrode. On the otherside of the frame 0 I placeanother side frame Z shown Fig. 4E betweenwhich and the frame 0 is clamped a layer ,orsheet of parchment m or amaterial having the qualities of parchment and ofwhich parchment is thetype. In the frame Z the negative electrode which may be a sheet of ironnetting is preferably secured adjacent theparchment sheetand serves toprevent said sheet from bulging toward the negative side of the cell.The positive wireis indicated at qand the negative wire at 0*. Thesewires are shown as connected with the positive and negative electroderespectively. Itis unnecessary to do more than indicate the connectionsas the details thereof are merely matters of electri cal engineering andwell known to those skilled in the art. The diaphragm proper, that isthe parchment layer m is separated from the layer or sheet of asbestos fby the thickness of the frame a and this may bevaried as desired withoutdeparting from my invention. The space betweenthe layers or sheets m andf is provided with brine which is supplied as desired to .the spaceshown at s Fig. 1 directly above the cross piece cl of the central frame0. This brine passes down through the holes 6 into the space below thesaid cross piece at and between the layers m and f. The level of theliquid in the intermediate space between said layers is maintained at ahigher level than the level a of the liquid outside said space. Thiscauses a flow of the liquid outwardly through the pervious asbestoslayer from the space between the layers m f toward the positiveelectrode side of the cell and thus serves to prevent the chlorine orany of the liquid containing chlorine from reaching the parchmentdiaphragm m. As the parchment is quite durable unless attacked by thechlorine its life isin this way prolonged and its efiectiveness secured.As the layer of asbestos f is not attacked by chlorine its fullefficiency is also obtained and a diaphragm of great durability andefficiency is the result. As previously stated the inter-diaphragm spacebetween the layers m f is supplied with fresh solution and as thissolution constantly flows through the pervious asbestus layer into thepositive compartment of the cell, the electrolyte supply for thepositive compartment is wholly orki largely furnished in this way. Theeifect of the excess of pressure due to the higher ,levelofthe liquid inthe inter-diaphragm space is to minimize and render of no importance thediffusion of chlorinated solution toward the parchment sheet whichelectrically considered is the diaphragm proper. It .willbe clear thatthe value of my device does not depend upon the use of either parchmentorasbestusfor the sheetsm f and I do not t herefore desire to confinemyself to suclr'sheets. Many substances maybe used in place ofthesematerials. As an equivalent for the parchment I may mention abich-romatized gelatine which has been rendered insoluble by exposure tothe sun-light and very thick woven cloth fabric. Inplace of the.asbestus thin porousearthenware may be. used.

In case the products ofdecompositionat the negative electrode issufficient to destroy or render it desirable to protect, the diaphragmor non-poroussheet m from their action the negative electrode may beremoved somewhat from the I said diaphragm-and a pervious sheet similarto the sheet f may be placed on the negativesideof thesheet m, inamanner similar to that in which it is shown as arranged on the positiveside in the drawings and the supply of the solution for the negativecompartment maybe caused to take place through this pervious sheet. Inother words the arrangement shown in Fig. 1 is for use in caseswhere theproducts of decomposition which are liberated at the negative electrodeare notsuch aswill attack theparchmentsheet. In case, however theseproducts are injurious to the parchment sheet and the parchment sheet{requires to be protected therefrom it is only necessary to duplicatethe pervious sheet shown in Fig. l on the negative side of the diaphragmproper thus providing for a flow of liquid from theintermediate spaceinto the negative compartment thus securing the diaphragm from attack onthat side. Such a construction is shown in Fig. 5. The central frame amaybe made by cutting it from heavy sheets of lead. The holes 6 in thecross bar (1 of said frame not onlyserve for the admission of thesolution but also for .the escape of any bubbles of gas which may beliberated in the inter-diaphragm space. The negative electrode frame Zis preferably of slate but it may be of high qualitystone ware or ofglass. The rods 70 are also preferably of glass.

The device employed for clamping the frames together is not shown butanywell known clamp may be employed.

The frames employed for supporting the diaphragm as also the pervioussheet or sheets may be varied as will be obvious in form andconstruction without departing from my invention, the important featureof which is the separation of the diaphragm proper from'the corrosiveproduct by the interposition of a pervious sheet and fresh liquid, thelatter flowing away from the diaphragm.

What I claim is- 1. An electrolytic cell having in combination with thediaphragm thereof a pervious sheet or layer interposed between saiddiaphragm and the electrode of the cell, and separated from saiddiaphragm by a space forming a chamber containing liquid under greaterrelative pressure than the liquid in the adjacent compartment ofthecell, whereby the movement of the liquid in the cell due to the saidgreater pressure will be from said diaphragm and through the pervioussheet or layer, substantially as set forth.

2. In an electrolytic cell, the combination with the diaphragm of'asheet or layer separated from said diaphragm and interposed between thesame and the electrode of the cell, and suitable frames for preventingsaid dia phragm and said pervious sheet from bulging under the pressureof the liquid, all substantially as described, and whereby the level ofthe liquid in the space between the diaphragm and the pervious sheet maybe maintained at a higher level than the level of the liquid in thecompartment of the cell, sub- 'stanti ally as set forth,

3. The combination with the cell A provided with a suitable overflow b,of the frame 0 provided with holes e, the diaphragmmand pervious sheet fat opposite sides of the frame a and the side frames g Z, for theelectrodes, placedrespectively beside the said pervious sheet and thediaphragm substantially as shown and described.

4. The combination with the frame a of the pervious layer f at one sidethereof and the frame g and rods 70, at the side of the pervious layersubstantially as shown and described. 5. The method of protecting thediaphragm of an electrolytic cell, which consists in first producing adiaphragm wall or layer of fluid between'the said diaphragm and thecontents of the cell adjacent to the said diaphragm, then occasioningpressure upon the fluid, and keeping the latter under pressure andthereby maintaining in the said fluid lateral pressure with tendency tolateral flow away from the diaphragm, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

ERNEST ARTHUR LE SUEUR.

Witnesses: WM. A. MACLEOD,

RoBT. WALLACE.

